Niger has no ideal window. No month clears the bar for comfortable travel outright, but Dec–Jan comes closest — rated fair rather than too hot, too cold or too wet.
Summer monsoon
| Month | High °C | High °F | Rainy days | Verdict |
|---|---|---|---|---|
| January | 32.1 | 90 | 0% | Fair |
| February | 35.4 | 96 | 0% | Too hot |
| March | 38.9 | 102 | 1% | Too hot |
| April | 41.0 | 106 | 5% | Too hot |
| May | 40.1 | 104 | 21% | Too hot |
| June | 37.4 | 99 | 54% | Too hot |
| July | 34.2 | 94 | 78% | Too hot |
| August | 31.6 | 89 | 88% | Too wet |
| September | 32.9 | 91 | 59% | Too wet |
| October | 36.1 | 97 | 15% | Too hot |
| November | 35.6 | 96 | 0% | Too hot |
| December | 32.9 | 91 | 0% | Fair |
Verdict combines mean daytime high with rainy-day frequency. “Rainy days” is the share of days in the month with at least 1 mm of rain.
January is the driest month, with rain on 0% of days and daytime highs near 32.1°C (90°F). August is the wettest, at 88%. The warmest month is April at 41.0°C (106°F); the coolest is August at 31.6°C (89°F). The record rules out too hot in Feb–Jul, Oct–Nov; too wet in Aug–Sep.